1. Field of the Invention
This invention relates to mower cutting implements having multiple cutting spindles and decks and more specifically to a spindle belt drive configuration that allows the decks to flex relative to each other without stressing the respective belts of the drive.
2. Description of Related Art
Mower cutting implements having multiple cutting blades ordinarily have separate decks or housings which enclose those blades. These decks are often hingedly connected together to allow each of the decks to flex or pivot independently and relative to another as the deck moves across the ground. Many times, mowers having this hinged connection between the decks are used in the care of grounds having a substantially uneven surface or contour. Accordingly, flexing between each of the decks permits grounds of this type to be uniformly maintained as each deck is able to follow the contour at a pre-set level of cut.
It is known that a common way to power the blades within the decks is to use a belt drive system utilizing pulleys and belts extending between the decks. Power for the decks is provided by a drive shaft connected with a mower""s power take off. The drive shaft transmits power to a central or main gear box on the central cutting deck. This gear box in turn rotates a main drive pulley and drives the center blade of the main or central deck. Power from this main drive pulley is transferred by endless belts to one or more other driven pulleys which drive blades housed within the adjacent decks.
Past designs have oriented these pulleys and belts to rotate within a plane generally parallel to the surface of the decks. Since each pulley rotates about its own vertically extending axis, the axes of the drive and driven pulleys are substantially parallel when the decks are operating on a generally level surface. As the decks move across uneven ground however, they will pivot and the axes of rotation of these pulleys no longer remain parallel to one other.
As the axes of the drive and driven pulleys become non-parallel, the belts entrained about them have often not been able to enter and exit the pulley grooves without being misaligned to some degree. Because of the misalignment, a number of disadvantages exist with respect to the pulleys and belts which rotate thereon. First, the belts wear easily and become frayed or torn as each deck pivots relative to the remainder of the deck. Wearing of this type occurs since the belts repeatedly twist and bend as they enter and exit the V-shaped flanges of the pulleys as the respective decks pivot. This causes stresses to be encountered by the belts resulting in their accelerated wear and eventual tearing since the belts are in motion when pivoting of the decks takes place. Accordingly, increased maintenance in terms of repair and/or replacement of the belts may occur more often than is necessary.
Second, the pulleys themselves and specifically their inner flanges may deform over time as the belts bear against the flanges when pivoting of the decks occurs. Third, the belts frequently become stretched or lengthened as a particular cutting deck repeatedly pivots upwardly and downwardly to accommodate the contour of the ground surface. This repeated vertical motioning of the belts stretches them. Consequently, the belts sometimes slip when entering the pulleys, thereby affecting operation of the cutting blades and therefore, the effectiveness of the overall cutting performance.
Thus, it would be beneficial to provide a configuration for a belt drive system that orients the pulleys to allow the belts to enter and exit the pulleys without twisting and without constriction as any one deck flexes or pivots with respect to the adjacent decks.
Accordingly, there is provided a belt drive system for a cutting implement having one or more pivotally connected decks. The belts transfer power between a drive pulley mounted with a first deck to a driven pulley mounted with a second and adjacent deck to rotate the blades housed within the decks. Third and fourth pulleys are provided to transfer power between the drive and driven pulleys. The third and fourth pulleys are fixed for rotation together and remain substantially above the pivotal connection of the decks, rotating about an axis that remains generally parallel to the rotational axes of the drive and driven pulleys as the decks pivot. Parallel alignment of these axes enables the belts entrained about the pulleys to enter and exit smoothly without twisting or being otherwise stressed.
To permit parallel alignment of the axes of rotation of the pulleys as the decks pivot and thereby enable the belts to move between the pulleys without having to twist, the pulleys are mounted with pivot arms that move the pulleys and the belts in reaction to movement of the decks. Movement of the belts into and out of the pulleys without their twisting occurs since the grooves thereof remain aligned as the deck pivots.
Alignment of the pulleys and their grooves is maintained throughout pivoting of the decks because the arms vertically reposition the pulleys in response to the deck pivoting. Vertical movement of the arms allows each pulley to be coaxial with its respective adjacent pulley so as to align the grooves of those pulleys and thereby avoid twisting and/or bending of the belts entrained thereabout when entering or exiting the pulleys.
Additionally, since the pulleys are moved relative to one another, they and their flanges are not stressed or otherwise deformed by the entry and exit of the belts since the grooves in which the belts move are always in substantial alignment. Consequently, the belts and associated pulleys on which they rotate will experience a longer operating life thereby reducing the need for frequent repair and/or replacement.
There is further provided a belt drive system that substantially retains the original length of the belts entrained about the pulleys as the decks repeatedly pivot upwardly and downwardly. Maintenance of this original length is accomplished through constructing the above pivot arms with two angular and fixed length sections or members connected together. Restricting each of these sections to a fixed length keeps the center distance between adjacent pulleys, i.e., the distance between the center point of one pulley and its adjacent pulley, constant at all times. Therefore, the likelihood of stretching the belts as the decks pivot is substantially reduced.
Thus, there is provided a belt drive system for a cutting implement having pivotally connected decks whereby the system enables the belts to travel smoothly into and out of the pulleys about which they are entrained as the decks pivot. Further, there is provided a system which substantially maintains the original length of the belts and also reduces the likelihood of deformation of the pulleys as the decks pivot.